The small print of the Pre-Budget Report means 90 per cent of bankers’ bonuses will still be paid out — despite the new tax.

But tens of thousands of poorer families will see the taxman taking 90 per cent of any extra money they earn.

The centrepiece of Alistair Darling’s mini-budget was a new one-off levy of 50 per cent on bank bonuses over £25,000.

The Chancellor claimed it would claw back a vote-winning £550million.

But the small print reveals the Treasury still expects £5billion to be paid in bonuses in April.

And City chiefs have already devised schemes to dodge the tax — like paying out bonuses early before the PBR came in on Wednesday.

But 70,000 low income families will face marginal tax rises under the new budget — which could leave many better off on BENEFITS.

The complicated new rates mean a lone parent who earns £200 a week instead of £100 will only end up with £6.80 extra. A couple with two kids and one parent in work can double their pay from £172 to £350 a week and only end up £10.83 better off by losing £104.19 in benefits and paying out £55.62 extra in tax.

In a double whammy to working families one in three small businesses said they will have to AXE staff because of the 1 per cent rise in National Insurance set out in the PRB.

Shadow Chancellor George Osborne said: “It is the many, not the few who are suffering under Labour.”